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From: bzs%bu-cs.bu.edu@bu-it.BU.EDU (Barry Shein)
Newsgroups: comp.unix.wizards
Subject: Jerry Pournelle on UNIX (From BYTE)
Message-ID: <11194@brl-adm.ARPA>
Date: 9 Jan 88 18:43:38 GMT
Sender: news@brl-adm.ARPA
Lines: 44


>imagine a root partition that consists of a zillion symlinks, initially
>pointing to the rom disk.  to change /bin/sh, just change the symlink.

I thought of that, but then why have a read-only root at all? Sounds
like all you're left with is the ability to say, without complete
dishonesty, "I have a read only root", sin of omission.

I think what we have here (in general, not this note) is hacker's
fever.  The reason you'd ROMify the unix root is because you want a
version that has several advantages (can't trash it) AND you
specifically were confident that people (probably turnkey users, not
hackers) did not want to change anything. I suppose you could
rearrange some configuration stuff, symlinks is as good as any (or a
different mechanism entirely, some stuff just won't live on root
anymore, at least as we know it, a few critical facts might get read
in at boot from a single file, like a default server host if that's a
thing.) Could be hard-coded into an editable /etc/rc file script I
guess.

Anyhow, the point is, either you want it or you don't. Too much
compromise (like a zillion symlinks) seems to obviate any advantage
pretty quickly.

It seems academic to me, I can't see any huge need that can't be
solved in some other way, except perhaps a true turnkey or process
control type application where it's just supposed to do the same thing
over and over again every day and no one wants to touch it, or at
least considers touching it a major enough event that changing a chip
is reasonable (can you say "ROM upgrade"?)

I know that the Mac has this huge rom with everything in it but I'm
not quite sure why they think that's a good idea other than perhaps it
helped them hit some cost goal, the thing still crashes at the drop of
the hat and doesn't even reboot or do anything intelligent, just sits
there with a cute system bomb message waiting for the user to do
something (if you're lucky, sometimes it just sits there catatonic.)

Sounds a little like "romifying is the answer...what's the question?"
Except, like I said, in a few special applications of a machine. Like
Ron Natalie pointed out you could mount a root disk read-only with
some not-so-drastic changes. Then they'd just get to trash /usr...

	-Barry Shein, Boston University